Wireless signaling system



No.- 749,370. PATENTED JAN. 12, 1904,

c. D. EHRET. WIRELESS SIGNALING SYSTEM. APPLICATION IILBI) NOV. 15,1902. R0 MODEL.

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UNITED STATES Patented January 12, 1904.

PATENT OEEIcE.

CORNELIUS D. EHRET, OF ARDMORE, PENNSYLVANIA, ASSIGNOR, BY MESNEASSIGNMENTS, TO INTERNATIONAL WIRELESS TELEGRAPH COMPANY, A CORPORATIONOF NEW JERSEY.

- WIRELESS SIGNALING SYSTEM.

SPECIFICATION forming part of Letters Patent No. 749,370, dated January12, 1904:.

Application filed November 15, 1902. -Seria1No. 131,484. (No model.)

To all 1.0750172, it may concern:

Be it known that I, CORNELIUS D. EHRET, a citizen of the United States,residing at Ardmore, in the county of Montgomery and State I ofPennsylvania, have invented certain new and useful Improvements inWVireless Signaling Systems, of which the following is a specil'ication.

My invention relates to wireless signaling systems in which the energyrepresenting the signal or message is in the electroradiant form and istransmitted through the natural media.

My invention consists of a method of transmitting intelligence by meansof electrical energyin electroradiant form, such method having referenceparticularly to the translation of the transmitted. energy into a signalor mes sage at the receiving-station.

My invention consists in increasing the current component of thereceived electroradiant energy after having been transformed into theenergy of currents in the receiving-circuits.

My invention consists also in increasing. the

current component of the current energy promitted energy, this increasebeing effected by the employment of a closed tuned circuit so duced inthe receiving-circuit by the transcuit and employing such increasedcurrent component for producing a signal in a device either of theelectrostatic type or else the magnetic type, such device or translatingdevice forming a part of or an entire frequency-determining element ofthe closed tuned circuit.

Reference is to be had to the accompanying drawings, in which Figure 1is a diagrammatic representation of the circuits at a receiver suitablefor carrying out the herein-described method. Fig. 2 is a diagrammaticview of the circuit of a re ondary is indicated at S. shown as astep-down transformer---that is,

ceiver whereby a plurality of messages may be simultaneously received,the electrorachant energy representing each message being subjected tothe series of steps above outlined.

In Fig. 1, A represents the usual aerial conductor of a wirelesssignaling system, between which and the earth connection E-is theprimary winding P of a transformer Whose see- This transformer is thecurrent in the secondary circuit is greater than that in the primary,though the potential of the secondary is less than that of the primary.C and L are an adjustable condenser and adjustableinductance,respectively. They are connected in parallel with each other,but in series with a secondary circuit. The electrorad iant energyreceived upon the aerial conductor A is of a fixed and definitefrequency. The frequency of the currents in the secondary circuit ofprecisely the same frequency, and by adjusting. the condenser C andinductance L the local circuit embracing said condenser C and inductanceL only may be made resonant with the currents of the critical frequencyexisting in the secondary circuit. It is of the essence of my inventionthat the condenser C and inductance L be adjusted to exact and preciseresonance with the frequency of the transmitted electroradiant energy,and

. therefore of the currents in the secondary circuit. Any departure,however slight, from this exact and precise adjustment would greatlyalter the effects produced in the antiresonant circuit in the directionof greatly re ducing the beneficial results. It is possible withimproper adjustment to approximate more or less closely the resultsIattain by my method; but it is my invention to adjust the antiresonantcircuit to precise resonance,

whereby the maximum and best eifect is procured.

As the translating device for reproducing the signals or messages may beemployed, for

example, an electrostatic telephonethat is, a condensertelephone, suchas is well-known in the arts. The condenser of the telephonereceiver ismade adjustable and is, in fact, then the condenser C of the closedtuned circuit, or the translating device may be of the electromagnetictypesuch for example, as a telephone-receiver comprising two flat coilsconnected in series, one of the coils being secured to the body of thetelephone-receiver, while the other is secured to the diaphragm. In thiscase the two coils in series would supplant the inductance L of theclosed tuned circuit, or both an electrostatic telephone-receiver orother device and an electromagnetic telephone-receiver or other devicemay be used simultaneously in the closed tuned circuit. ith sucharrangement the electrostatic telephone-receiver might be held to oneear, while the electromagnetic telephone-receiver might be held to theother ear.

Though I have shown the closedtuned circuit as included in the secondaryof a transformer, I may include the same directly in the aerial circuit.

In Fig. 2, A represents the usual aerial conductor, and associatedtherewith are the two branch circuits, including adjustable inductance Iand primary 1) and the adjustable inductance I and the primary 9,respectively. The aerial conductor A, taken in conjunction with each oneof these branch circuits, forms a receiving aerial circuit selective ofa predetermined frequency of electroradiant energy. By this means aplurality of energies of different frequencies may be simultaneouslyreceived and properly selected to the desired recording-circuit. Theinductances I and I are made adjustable for the purpose of properlytuning the aerial circuit. The primaries p p afford a portion of theinductance for each branch circuit. At 8 is shown the secondary of thetransformer whose primary is p, there being included in the circuit ofthis secondary the closed tuned circuit, including the adjustableinductance L and adjustable condenser C, which are so adjusted withrespect to each other that they will form a closed local circuit sharplyresonant with the frequency of the energy selected to the branchcircuit, including the primary 1). Similarly at s is shown the secondaryof the transformer whose primary is p. In the circuit of this secondaryis included the second antiresonant circuit, including inductance L andcondenser C, both adjustable. The closed tuned circuit C L is adjustedto sharp resonance with the frequency of the energy selected by thebranch circuit, including the primary 1).

By the arrangement shown in Fig. 2, therefore, the plurality of messagesmay be simultaneously received and recorded, such messages beingrepresented by energy of characteristic frequency.

When the closed tuned circuits herein shown and described are properlyadjusted to precise resonance, there will circulate in them currents ofa magnitude far in excess of the actual current in the secondary circuitor the circuits in which the closed tuned circuits are included inseries. In order, however, that this current shall be a maximumthat is,that the current component of the current energy in the secondary orother circuits shall be increased to a maximum the adjustments of thecapacity and inductance of the closed tuned circuits must be such as tosecure exact resonance.

This application discloses subject-matter shown and described in myapplication, Serial No. 84,514, filed December 8, 1901.

What I claim is 1. The method of rendering intelligible electroradiantenergy transmitted through the natural media, which consists intransforming the electroradiant energy into the energy of electriccurrents, and increasing the current component of said energy ofelectric currents by supplying said energy to a circuitincluding aclosed resonant circuit comprising capacity and inductance arranged inbranches which a re in parallel with each other.

2. The method of rendering intelligible electroradiant energytransmitted through the natural media, which consists in transformingsaid electroradiant energy, into the energy of electric currents,increasing the current component of said energy of electric currents bysupplying it to a circuit including a closed resonant circuit comprisingcapacity and inductance arranged in branches which are connected inparallel with each other, and causing said increased current componentto actu ate or control a signal-producing device.

3. The method of rendering intelligible electroradiant energytransmitted through the natural media, which consists in transformingsaid electroradiant energy into the energy of electric currents,increasing the current component of said energy of electric currents bya step-down transformer, and further increasing the current component bysupplying said energy to a circuit including a closed resonant circuitcomprising capacity and' inductance arranged in branches which areconnected in parallel with each other.

t. The method of rendering intelligible electroradiant energytransmitted through the natural media, which consists in transformingthe electroradiant energy into the energy of electric currents, andincreasing the current component of said energy of electric currents bysupplying it to branches connected in parallel with each other andincluding respectively inductance and capacity so adjusted andproportioned as to render the closed circuit formed by said branchesresonant with respect to the transmitted electroradiant energy.

5. The method of rendering intelligible electroradiant energytransmitted through the natural media, which consists in transformingthe electroradiant energy into the energy of t0 the transmittedelectroradiant energy, and

utilizing a frequency-determining element as a signal-producing means. 7

CORNELIUS D. EHRET.

Witnesses:

ALICE T. BURROUGH, MAE HOFMANN.

